/*
 *  An 32-bit implementation of the XTEA algorithm
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 *
 *  This file is provided under the Apache License 2.0, or the
 *  GNU General Public License v2.0 or later.
 *
 *  **********
 *  Apache License 2.0:
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  **********
 *
 *  **********
 *  GNU General Public License v2.0 or later:
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *  **********
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "nettls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_XTEA_C)

#include "nettls/xtea.h"
#include "nettls/platform_util.h"

#include <string.h>

#if defined(MBEDTLS_SELF_TEST)
#if defined(MBEDTLS_PLATFORM_C)
#include "nettls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf printf
#endif /* MBEDTLS_PLATFORM_C */
#endif /* MBEDTLS_SELF_TEST */

#if !defined(MBEDTLS_XTEA_ALT)

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n, b, i) \
    { \
        (n) = ((uint32_t)(b)[(i)] << 24) | ((uint32_t)(b)[(i) + 1] << 16) | ((uint32_t)(b)[(i) + 2] << 8) | ((uint32_t)(b)[(i) + 3]); \
    }
#endif

#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n, b, i) \
    { \
        (b)[(i)] = (unsigned char)((n) >> 24); \
        (b)[(i) + 1] = (unsigned char)((n) >> 16); \
        (b)[(i) + 2] = (unsigned char)((n) >> 8); \
        (b)[(i) + 3] = (unsigned char)((n)); \
    }
#endif

void mbedtls_xtea_init(mbedtls_xtea_context* ctx)
{
    memset(ctx, 0, sizeof(mbedtls_xtea_context));
}

void mbedtls_xtea_free(mbedtls_xtea_context* ctx)
{
    if (ctx == NULL)
        return;

    mbedtls_platform_zeroize(ctx, sizeof(mbedtls_xtea_context));
}

/*
 * XTEA key schedule
 */
void mbedtls_xtea_setup(mbedtls_xtea_context* ctx, const unsigned char key[16])
{
    int i;

    memset(ctx, 0, sizeof(mbedtls_xtea_context));

    for (i = 0; i < 4; i++) {
        GET_UINT32_BE(ctx->k[i], key, i << 2);
    }
}

/*
 * XTEA encrypt function
 */
int mbedtls_xtea_crypt_ecb(mbedtls_xtea_context* ctx, int mode, const unsigned char input[8], unsigned char output[8])
{
    uint32_t *k, v0, v1, i;

    k = ctx->k;

    GET_UINT32_BE(v0, input, 0);
    GET_UINT32_BE(v1, input, 4);

    if (mode == MBEDTLS_XTEA_ENCRYPT) {
        uint32_t sum = 0, delta = 0x9E3779B9;

        for (i = 0; i < 32; i++) {
            v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
            sum += delta;
            v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
        }
    } else /* MBEDTLS_XTEA_DECRYPT */
    {
        uint32_t delta = 0x9E3779B9, sum = delta * 32;

        for (i = 0; i < 32; i++) {
            v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
            sum -= delta;
            v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
        }
    }

    PUT_UINT32_BE(v0, output, 0);
    PUT_UINT32_BE(v1, output, 4);

    return (0);
}

#if defined(MBEDTLS_CIPHER_MODE_CBC)
/*
 * XTEA-CBC buffer encryption/decryption
 */
int mbedtls_xtea_crypt_cbc(mbedtls_xtea_context* ctx, int mode, size_t length, unsigned char iv[8], const unsigned char* input, unsigned char* output)
{
    int i;
    unsigned char temp[8];

    if (length % 8)
        return (MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH);

    if (mode == MBEDTLS_XTEA_DECRYPT) {
        while (length > 0) {
            memcpy(temp, input, 8);
            mbedtls_xtea_crypt_ecb(ctx, mode, input, output);

            for (i = 0; i < 8; i++)
                output[i] = (unsigned char)(output[i] ^ iv[i]);

            memcpy(iv, temp, 8);

            input += 8;
            output += 8;
            length -= 8;
        }
    } else {
        while (length > 0) {
            for (i = 0; i < 8; i++)
                output[i] = (unsigned char)(input[i] ^ iv[i]);

            mbedtls_xtea_crypt_ecb(ctx, mode, output, output);
            memcpy(iv, output, 8);

            input += 8;
            output += 8;
            length -= 8;
        }
    }

    return (0);
}
#endif /* MBEDTLS_CIPHER_MODE_CBC */
#endif /* !MBEDTLS_XTEA_ALT */

#if defined(MBEDTLS_SELF_TEST)

/*
 * XTEA tests vectors (non-official)
 */

static const unsigned char xtea_test_key[6][16] = {
    {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
    {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
    {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}};

static const unsigned char xtea_test_pt[6][8] = {{0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48}, {0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41},
                                                 {0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f}, {0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48},
                                                 {0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41}, {0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55}};

static const unsigned char xtea_test_ct[6][8] = {{0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5}, {0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8},
                                                 {0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41}, {0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5},
                                                 {0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d}, {0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41}};

/*
 * Checkup routine
 */
int mbedtls_xtea_self_test(int verbose)
{
    int i, ret = 0;
    unsigned char buf[8];
    mbedtls_xtea_context ctx;

    mbedtls_xtea_init(&ctx);
    for (i = 0; i < 6; i++) {
        if (verbose != 0)
            mbedtls_printf("  XTEA test #%d: ", i + 1);

        memcpy(buf, xtea_test_pt[i], 8);

        mbedtls_xtea_setup(&ctx, xtea_test_key[i]);
        mbedtls_xtea_crypt_ecb(&ctx, MBEDTLS_XTEA_ENCRYPT, buf, buf);

        if (memcmp(buf, xtea_test_ct[i], 8) != 0) {
            if (verbose != 0)
                mbedtls_printf("failed\n");

            ret = 1;
            goto exit;
        }

        if (verbose != 0)
            mbedtls_printf("passed\n");
    }

    if (verbose != 0)
        mbedtls_printf("\n");

exit:
    mbedtls_xtea_free(&ctx);

    return (ret);
}

#endif /* MBEDTLS_SELF_TEST */

#endif /* MBEDTLS_XTEA_C */
